It is advantageous for electrical systems to be power efficient. Therefore, reducing power consumption in the system is desirable. One way to reduce power consumption in an electrical circuit is to have a low power mode (e.g., a sleep mode) that a circuit may operate under while the circuit is not performing tasks. Once the circuit is needed by the system, a wakeup signal is generated to power up the circuit so that it may operate as intended. For example, in battery operated cars, it is preferable that the automotive Ethernet be power efficient to reduce energy use by the battery. Therefore, the Ethernet physical layer (PHY) can be placed in a low power sleep mode when it is not transmitting or receiving data. The Ethernet PHY is powered up once there is data toggling on the line. A detection circuit can be utilized to determine whether data is toggling on the line. Once the data is detected, a wakeup circuit can generate a wakeup signal causing the Ethernet PHY to power up (wakeup). In this way battery power is conserved.